Apparatus for coating lithographic plates



March 16, 1937.

R. FRri'scH APfARATUS FOR COATING LITHOGRAPHIC PL ATES 3 Sheets-Sheet l Filed July 24, 1936 INVENTOR Rudo Zf Wifsche BY Y I W ATTORNEYS;

WITNESSES March 16, 1937. R. FRITSCHE APPARATUS FOR COATING LITHOGRAPHIC PLATES 3 Sheets-Sheet 2 ,Filed July 24, 1936 :r III OR Ru oZo gf Frzi's eke WITNES ES ATTORNEY March 16, 1937.- R. FRITSCHE 2,074,171

APPARATUS FOR COATING LITBOGRAPHIC PLATES Illllllllll WITNESSES INVENTO R Rudolf Fr'iische gi (f z wlt A a I m ATTORNEYS Patented Mar. 16, 1931- I Rudolf Frltsche, New York, N. Y. Ap l cation July 24.21936. Serial No. 92,387.

This invention relates to an improved apparatus forcoating lithographic plates, an objectbeing to provide an improved construction: wherein there will be produced. Another object of the invention is to provide an substantially no faulty plates apparatus with means for receiving and holding:

sensitized material which has been sprayed 'or discharged from the plate when being coated with asensitizing liquid. i

A further object is to provide an apparatus for coating with a sensitizing liqiiid a plate and at the same time hold all foreign matter away from In the accompanying drawings: Fig, 1 is a sectional view through Fig. 2 on the line l--l, the same disclosing the principal the plate during the coating and drying thereof.

. features of an apparatus for-coating lithographic plates; p a Fig. 2 is a sectional view through Fig. 1, the

same being taken on the line 2-2 and disclosingan embodiment of the invention;

Fig. 3 is a horizontal sectional view through Fig. 1 approximately n the line 39; Fig. 4 1s a furt er'elevation of the structure shown in Fig. 2;

Fig. 5 is an elevation of shown in Fig.2; d Fig. 6 is an enlarged fragmentary sectional view through Fig. 5- on theline 6-6;

' FlFlg. '7 is an elevation ofthe clamp shown in g. Fig. 8 is an enlarged through Fig. 5 on the the plate coating frame line 8-8.

. 5 In the manufacture of lithographic plates it is necessary to apply the sensitizing liquid or solution to the plate-and then to spread the solution evenly over'the plate. After this has been done the solution is allowed to dry. Heretofore devices known as whirlers have-been used for rapidly"ro-= tating the plate after the sensitizing liquid has.

been deposited thereon whereby the sensitizing material will be spread evenly over the plateand some of the material will be impelled or sprayed 5 radially outwardly against the walls 'of-the apparatus in which the plate has been mounted.-

' After several plates have been coated, it has been found that some of the previously sprayed material is loosened and drops on to the new plate,

50 thus forming a defect in the plate. Various means have been provided to obviate this objecthin with varying successes. In the present invention means have been provided not only for whirling the plate, drying the same and confining the plate in a housing, but also for receiving and fragmentary sectional view hol fig any sprayed material or other matter lea g the plate so that each succeeding plate is never subjected to the possibility of having foreign matter dropped thereon.

Referring to the accompanying drawings by numerals-i indicates a frame of any desired kind and provided with suitable uprights and cross I bars forholding the various parts hereinafter fully described. Mounted on frame I is a housing 2 which may be circularjor may be square as shown in Figs. 1 and 4 This housing is arranged vertically and is open on one side. A suitable door structure 9 is provided for closing the opening in the. housing. While various forms of door structures, may be used, it' has been found desirable to provide a door structure having a number of inter-engaging sliding'sections 4 and 5. These groups of sections may be locked together by a suitablecatch 6. 'I'he'upper and lower ends of these sections are accommodatedby the channels I andB as shown in Figs. 2 and 4. v It will beunderstood that the casing i is stationary but arranged withinthis casing is pro,- vided-a member 9 which may be called acontainer. Container 9 is preferably circular with -the axis in ahorizontal plane. Container 9 always in-line with the opening in the casing l which is closed by door 3. Anydesired number .of rollers It and iii are provided and carried by the casing I, said rollers being'pos'itioned to prevent the container 9 from. oscillating and to hold the same in a'vertical plane while permitting free rotation thereof. Supporting and'driving rollers "i6 and "are arranged near the lower part of casing l as shown in'Fig. 1, and on these rollers the container 9 is mountedfIn fact, the container 9 is supportedbyrollers Iii and I! while being guided by the upper rollers l8 and i9.

These rollers are flanged as shown in Fig. 2 so as to help maintain the container 9 in a vertical position at all times.

, A horizontally positioned driving shaft 20 is carried by the casing I and preferably extends loosely through the container 9'where a frame 2i is mounted. The frame 2| as shown in Fig. 5 has a central piece 22 provided with a central steadying pin .23 and radiating arms 24, 25, 26 and 21. Arms 25 and 21 are provided with slid- I ingclamps 28 which are formed as shown in Figs. 7 and 8. Each of these clamps is provided with an aperture 29 and a notch .30 having one flat straight wall 3| against which the plate 32' is pressed by the set screw 33} Set screws 34 and 35 lock the clamp 28 at different adjusted positions along the arm 25 or the arm 21 as the ii case may be. Arms 24 and 26 accommodate the respective-fittings 36 and each of these fittings is provided with a cross arm. :Each of the cross arms is provided with a clamp 28 which functions in the same manner on the arms 31 as it does on arms 25 and 21. A set screw 38 on the respective fittings 36 acts to lock the fitting at any desired point along the respective-arms 24 and 23. The various clamps 23 are adjusted to accommodate the plate 32 and may be adjusted to accommodate a very large plate or a very small plate. I

After the plate has been mounted on th frame 2| as shown in Fig. 2, the sensitizing liq d may be poured thereon and preferably the pourin starts at the center of the plate while the plate is rotating and the pouring instrument is moved slowly toward the periphery. After the pouring has stoppedthe plate continues to rotate at a comparatively high speed and thereby evenly distributes the light sensitive material under the action of centrifugal force and also gravity as the plate is in a vertical plane at all times. In

order to secure a proper rotation of the plate' the frame 2| is secured to shaft 23 by any suitable means, as for instance the set screw 39. Shaft 23 is. suitably journaled in frame I and carries a large pulley wheel 43 at one end. The belt 4| passes over pulley wheel 43 and also over a small pulley 42 connected to the movinil 5 part of the prime mover 43. The prime mover 43 maybe an electric motor or any other suitable source of power. A sprocket wheel 44 is also rigidly secured to shaft 23 as shown in 1'18. 2, and a suitable chain 43 passes over sprocket 40 wheel 44 and also over the sprocket wheel 43 which are rigidly secured to the respective shafts 41 and 43 carrying the driving rollers I3 and II.

It will be understood that the rollers l3 and i1 5 drive by friction. The respective parts just described are so proportioned that the container 3 will rotate at a comparatively slow speed, while the frame 2| will rotate at a comparatively high speed. For instance, frame 2i may have fifty so revolutions per minute while the container may have only nine revolutions per minute or even A supply of water 49 is maintained in the container 3 and as the container slowly-rotates the entire'inner surface of the peripheral part of the container will be moistened by its contact with the supply of water. This inner surface being continually wet and continually washed by the water 43 will receive and hold any material prolooted against the same. In fact, any of the light sensitive material which is projected against member I I will be eventually washed off and held in more or less suspension in water 43 at the bottom of the container. It will be understood that .3 the container I moves at such a slow speed that the supply of water 43 will always remain at the bottom at the container though it will maintain the inner peripheral surface of the container wet and will wuhoi! any particles deposited on 70 said surface. In this way the inner surface, of

theoontsinsriicontinuallymaintainedclean so that it'will b mpossible forany particles to drop therefrom onto the plate being coated. From time to, time the water 43 is drawn of! through 7 the normally closed outlet ll snd discharged into a drain 5|. New and clean water is then-provided. A sufllcient quantity of water is provided so that the depth of water will be almost up to the bead 52..

As soon as the light sensitive material has been properly. distributed over plate 32, heated air is passed over the plate so as to quickly dry the same. Various means may be provided for supplying heated air. As one. example heated air from a supplyplpe may be directed into the container or air at atmospheric temperature may be allowed to enter and be heated by suitable means, as for instance'anelectrical h r, gas heater, or the like. As shown in Fig.1 there are provided suitable gas heaters I3 and 34 arranged in These fans are formed and positioned to suck or draw the air upwardly and discharge the same out the top portion of the casing 2 as indicated by the arrows l4 inl'lg. 2.

It will be understood that the plate is rotating at a comparatively high rate of speed while the air is circulating. thereover, and consequently the light sensitive material is maintained in its uniformly spread condition while drying. When it is desired toremove the plate the prime mover 43 is stopped and the heat is turned off, though this is not absolutely necessary; However, as soon as the plate stops the door, 3 is opened by unlatching the catch 3 and pushing the panels or sections 4 and .I in opposite directions along their slides or guideways. This will fully expose the plate and the clamping screws holding the "same may be loosened and the plate readily removed manually. A new plate may then be supplied and the operation repeated. If the appsratus is in use continuously there will be no chance of any deposits ,to be made on the inner surface of the peripheral member II, and consequently the probability 1 of any foreign matter dropping on any plate while the same is being coated is reduced to a minimum. Also at the end of the days work it is only necessary to remove the water 49 and the apparatus is left clean for the night. i

It will be understood that the frame 2| maybe rotated at various speeds andalso the container 8 without departing from the spirit of the invention. Howevenit is also to be noted that all of these members are arranged in vertical planes which permits a proper spreading of the coating material and also permits the water 43 to continually wash the interior peripheral surface of the container 3 so that it will always be clean. In addition, this arrangement permits the use of.

a large apparatus for coating a large plate while utilizing a minimum amount of floor space.

I claim:

1. In a machine for coating a plate with light sensitive material, a container of generally eylin, 1 drical form, the axis of said container extending in a horizontal plane, a plate supporting frame positioned in said container and mounted to rotate in a vertical plane, said container having one side formed with a centrally positioned openin said container being adapted to receive a supply of water, means for rigidly clamping a holding a plate to be coated, means for rotating said frame and plate carried thereby at a comparatively high speed, a rotating container substantially surrounding said plate, said container being adapted to contain a quantity of water,

and means for rotating said container at a speed comparatively slow. in respect to the rotation of said frame whereby said water will continually wash the interior surface of the peripheral part of the container. i

3. An apparatus for coating plates with a light sensitive material comprising a frame mounted to rotate in a vertical plane, means on the frame for clamping a plate to be coated, means for ro-. tating said frame and plate carried thereby at a comparatively high speed, a rotatable container substantially surrounding said plate and frame but not contacting therewith, said container being adapted to contain aquantity of water, and means for rotating said container at a speed comparatively slow to the speed of said frame, the rotation of said container being such that said water will remain at the lowest point of the container but will wash the interior surface of the peripheral part of the container as the container moves.

4. An apparatus for coating plates with a light sensitive material comprising a frame.

mounted to rotate in a vertical plane, means for clamping a plate tobe coated onto said frame, a,containersurrounding said frame and plate but not contacting therewith, said container being substantially formed in the shape of a drum with the axis in a horizontal plane, the container being adapted to contain a supply of water, and driving means for rotating said frame and container, said driving means causing the frame to rotate at a comparatively high speed and the container at a comparatively low speed, the speed of the container being such that the water therein will remainsubstantially at the lowermost point but will wash the interior peripheral surface of the'container as the container rotates.

5. An apparatus for coating plates with a light sensitive material comprising a plate supporting. frame positioned to rotate in a vertical plane,

a rotatable drum surrounding said frame, means' .for rotating said frame at a comparatively high speed, means for rotating said drum at a comparatively low speed, and means for causing warm air to pass over the plate carried by said frame during the rotation of the frame.

6. An apparatus for coating a plate with a light sensitive material comprising a rotatable drum of relatively large diameter and shallow depth, the axis of said drum being in a horizontal plane, a casing surrounding said drum, drum driving rollers arranged within said casing acting to support and rotate said drum, means for supporting a plate in said drum, a horizontally extending shaft for rotating said plate in a vertical plane, means for rotating said plate at a comparatively high speed and said rollers so that the drum willrotate at a comparatively slow speed.

7. An apparatus for coating a plate with a light sensitive material comprising a rotatable container having an opening in one side formed with a peripheral channel adapted'to receive a quantity of water, a casing surrounding said container, -driving rollers for supporting anddriving said container so that it will rotate at a speed which will permit the water therein to remain substantially at the lowermost point while washing the walls of said-channel, a frame mounted in said container in a horizontal plane, means for clamping a plate onto said frame, and means for rotating said frame and plate in a vertical plane.

8. An apparatus for coating a plate with a light senstive material comprising a rotatable container, a casing surrounding said container and provided with a door opening, a pair ofslideways carried by the casing adjacent the door opening, a door for closing said door open- 4 ing comprising a plurality of slide panels, means within the container for supporting a plate, means for rotating said plate in a vertical plane, and means for rotating said container at a speed slower-than the speed of said plate. v

BUDOLF FRI'rscHE. 

